[U] public async Task Urls()
 {
     var indices = Nest.Indices.Index <Project>().And <CommitActivity>();
     var index   = "project";
     await UrlTester.HEAD($"/{index}")
     .Fluent(c => c.Indices.Exists(index, s => s))
     .Request(c => c.Indices.Exists(new IndexExistsRequest(index)))
     .FluentAsync(c => c.Indices.ExistsAsync(index))
     .RequestAsync(c => c.Indices.ExistsAsync(new IndexExistsRequest(index)))
     ;
 }
 [U] public async Task Urls()
 {
     var indices = Nest.Indices.Index <Project>().And <Developer>();
     var index   = "project%2Cdevs";
     var types   = "_doc";
     var type    = "_doc";
     await UrlTester.HEAD($"/{index}/_mapping/{type}")
     .Fluent(c => c.Indices.TypeExists(indices, types))
     .Request(c => c.Indices.TypeExists(new TypeExistsRequest(indices, types)))
     .FluentAsync(c => c.Indices.TypeExistsAsync(indices, types))
     .RequestAsync(c => c.Indices.TypeExistsAsync(new TypeExistsRequest(indices, types)))
     ;
 }